There is a storage cluster as one of technologies that improve reliability of storage devices. The storage cluster has a cluster structure constituted by a plurality of storage devices and is a technology that implements a failover in which, even if one of the storage devices is down due to a failure at a device level, business can be continued by another storage device.
The storage cluster can be set in units of volumes and automatically takes over Write/Read I/O of a storage device in which a failure has occurred to another storage device. Accordingly, this makes it possible for a user to continue the business without being aware of the occurrence of an abnormality and thus it is possible to reduce the recovery time and the workload imposed on a storage administrator.
A volume in the storage cluster can be implemented by allowing a host to indicate the volume as, for example, another path of the same volume. The “host” mentioned here is a device, such as a server or the like, that accesses the storage device, whereas the “path” mentioned here is a communication path between the host and the storage device. In the storage cluster, the path in operation is used as “active”, the path on the waiting side is used as “standby”, and only the active storage device can be accessed. If the storage device in operation is down, the storage cluster changes a path state, sets the path on the waiting side to active, automatically takes over Write/Read I/O.
Furthermore, regarding a storage cluster, there is a technology that implements an asynchronous remote copy that is used for a disaster recovery by performing a pair operation of an asynchronous remote copy by asynchronously working with an instruction to change a host writing destination volume in a storage clustering environment.
Furthermore, regarding a volume change, there is a technology that suppresses ID exhaustion in a host by changing a request for an access to a change source volume to a change destination volume by referring to a change table in which a change source volume ID in the host is associated with a change destination volume ID in the storage.    Patent Document 1: Japanese Laid-open Patent Publication No. 2011-76130    Patent Document 2: Japanese Laid-open Patent Publication No. 2006-309638
When an operation is performed with respect to a volume, a host converts a device name, of an operation target, that is commonly set for the storage devices to a logical unit number (LUN) and specifies the operation target by the LUN. The “LUN” mentioned here is an identification number for logically identifying a device for storage in the storage device.
Furthermore, in the plurality of storage devices constituting volumes in the storage cluster, the device names are made to match between the active and the standby storage devices; however, the LUNs do not need to be matched. The reason for this is that, in order to match LUNs of the active storage device and the standby storage device, the same configuration is needed in both the storage devices; therefore, the load imposed on an administrator is significantly increased. Accordingly, in the present state, LUNs are not made to match in most cases even if storage devices have association relationship of the active side and the standby side.
However, if a failover occurs when an operation of specifying a LUN of a volume in a storage cluster is performed, because the LUNs do not match between the volumes associated with the active side and the standby side, there is a problem in that a false volume is operated after the failover.